perfectly round; perfect circle
Used as a noun or na-adjective for a shape that is completely round, such as a circle, disk, full moon, or round object. The variants 真ん円 and まん円 belong mainly to this literal sense.
The full moon looked perfectly round.
フリーハンドできれいな真ん丸を描くのは難しい。
It is hard to draw a neat perfect circle freehand.
adorably round; cute
Only when written 真ん丸 / まん丸
Affectionate, casual use, especially in speech by women or children, for something cute because it is round, plump, or round-eyed. It is not a general replacement for 可愛い.
このハムスター、まん丸でかわいい！
This hamster is so adorably round!
まん丸なほっぺの赤ちゃんがにこっと笑った。
The baby with cute round cheeks gave a little smile.
The moon in the sky was perfectly round.
The baby's perfectly round face is so cute.
She widened her eyes in surprise.
A perfectly round ball rolled across the yard.
Less common variant using 円 for the circle sense; best treated as limited to the literal 'perfect circle/round' meaning.
Rare mixed-kana variant for the literal round/circle sense.